In healthy subjects, only small amounts of bile acids are eliminated in urine. However, high Sulfated Bile Acids (SBA) concentrations can lead to the formation of water-soluble conjugate forms that can be rapidly eliminated in urine. These are primarily sulfated moieties that have a 10-fold renal clearance compared with non-sulfated forms. Sulfation of bile acids is not unique as sulfation of hydroxylated compounds by the liver is a well-established method of detoxification of a wide range of endogenous metabolites and xenobiotics. Renal excretion of sulfated bile acids is thought to represent an important excretory mechanism when high SBA accumulates. These urinary bile acid sulfates (UBAS) reflect an average of the SBA concentrations during the interval of urine formation. Normalization of the UBAS concentration using the urine creatinine concentration eliminates the influence derived from urine concentration.

UBAS has been approved by the FDA. Extensive clinical trials have demonstrated the efficacy of the method:

• A study conducted by the Kobe University Medical Center on 383 subjects showed that 60 normal controls all had low UBAS while of the 323 patients with impaired hepatic function (cirrhosis, hepatitis, carcinoma) as proven by biopsy, 81% had elevated UBAS levels.
  
• A study of 200 randomly selected patients at the VA Medical Center, Brooklyn N.Y., showed that the sensitivity of UBAS equaled the conventional serum enzyme tests (ALT, AST, GGT) as a marker for liver disease. In a separate study of 30 patients confirmed for HCV by PCR-RNA, the sensitivity of UBAS was equivalent to ALT and AST.
  
• A study of 100 patients with confirmed HCV by PCR-RNA at the St. Louis University Medical Center Department of Gastroenterology (Dr. Bruce Bacon, Principal Investigator), showed identical percentages of patients with elevated UBAS and elevated ALT.
  
• A study of over 3000 applicants for life insurance showed that for those persons with all serum liver enzymes within normal range, 98% had UBAS below the normal cutoff point.

Click here for a diagram illustrating hepatobiliary diseases that have been identified and corrected with the UBAS

UBAS Reference Ranges

Males: 1.0 - 8.0 umol/g cre
Females: 1.0 - 12.0 umol/g cre
Reference ranges not established for children < 10 yrs. old

Males: Ideal range < 6
8 - 12 range = mildly impaired liver function

Females: Ideal range < 9
12 - 15 range = mildly impaired liver function

Males > 12 and females > 15 indicate Hepatocellular damage. Assessment of Hepatobiliary diseases and prescription drug intake is indicated.

References
1. G.P. van Berge Henegoiwen, et.al. Gut, 17, 861 (1976).
2. P. Czgan, et.al., Frontiers of Liver Disease, Thime-Stratton, New York, 19-36, (1981)
3. V. Simko, et.al., Hepatology, 7, 115 (1987).
4. Y. Tazuke, et.al., Japan Journal of Clinical Chemistry, 21, 249 (1992)
5. FDA 510(k) #K9805525/993941
6. V.Simko, Proceedings of the 6th International Symposium on Hepatitis-C and related viruses, National Institutes of Health, Bethesda, Maryland, June 6-9, 1999.